One vertex per element, one color per generator, with an edge from x to x·s.
(9,10)(11,20)(12,13)(14,24)(15,17)(16,21)(18,23)(19,22)(25,26)(27,36)(28,30)(29,33)(31,35)(32,37)(34,40)(38,39) involution — undirected(1,2)(3,6)(4,5)(7,8)(9,11,15,21)(10,16,17,20)(12,22,23,14)(13,24,18,19)(27,37)(29,38)(32,36)(33,39)(2,5)(3,7)(10,17)(11,21)(12,23)(19,24)(25,27,31,37)(26,32,35,36)(28,29,34,38)(30,39,40,33)(3,7)(6,8)(9,12)(10,18)(11,22)(13,17)(14,21)(15,23)(16,19)(20,24)(25,28,31,34)(26,30,35,40)(27,38,37,29)(32,33,36,39)(1,3,4,7)(2,6,5,8)(9,13,15,18)(10,12,17,23)(11,19,21,24)(14,20,22,16)(25,29,31,38)(26,33,35,39)(27,28,37,34)(30,32,40,36)(1,2)(3,6)(4,5)(7,8)(9,14,15,22)(10,19,17,24)(11,12,21,23)(13,20,18,16)(25,30)(26,34)(27,33)(28,35)(29,32)(31,40)(36,38)(37,39)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.